This can happen in some compression modes of DjVu as well at high compression factors, where the background and foreground is separated and the foreground (text

This can happen in some compression modes of DjVu as well at high compression factors, where the background and foreground is separated and the foreground (text, usually) is split into glyphs that can be shared by different instances. Mess up the recognition and the letters on the page appear literally different in the compressed "oulput".